Chapron Bertrand

No Thumbnail Available
Last Name
Chapron
First Name
Bertrand
ORCID

Search Results

Now showing 1 - 3 of 3
Thumbnail Image
Article

Global observations of fine-scale ocean surface topography with the surface water and ocean topography (SWOT) mission

2019-05-15 , Morrow, Rosemary , Fu, Lee-Lueng , Ardhuin, Fabrice , Benkiran, Mounir , Chapron, Bertrand , Cosme, Emmanuel , d’Ovidio, Francesco , Farrar, J. Thomas , Gille, Sarah T. , Lapeyre, Guillaume , Le Traon, Pierre-Yves , Pascual, Ananda , Ponte, Aurélien

The future international Surface Water and Ocean Topography (SWOT) Mission, planned for launch in 2021, will make high-resolution 2D observations of sea-surface height using SAR radar interferometric techniques. SWOT will map the global and coastal oceans up to 77.6∘ latitude every 21 days over a swath of 120 km (20 km nadir gap). Today’s 2D mapped altimeter data can resolve ocean scales of 150 km wavelength whereas the SWOT measurement will extend our 2D observations down to 15–30 km, depending on sea state. SWOT will offer new opportunities to observe the oceanic dynamic processes at scales that are important in the generation and dissipation of kinetic energy in the ocean, and that facilitate the exchange of energy between the ocean interior and the upper layer. The active vertical exchanges linked to these scales have impacts on the local and global budgets of heat and carbon, and on nutrients for biogeochemical cycles. This review paper highlights the issues being addressed by the SWOT science community to understand SWOT’s very precise sea surface height (SSH)/surface pressure observations, and it explores how SWOT data will be combined with other satellite and in situ data and models to better understand the upper ocean 4D circulation (x, y, z, t) over the next decade. SWOT will provide unprecedented 2D ocean SSH observations down to 15–30 km in wavelength, which encompasses the scales of “balanced” geostrophic eddy motions, high-frequency internal tides and internal waves. This presents both a challenge in reconstructing the 4D upper ocean circulation, or in the assimilation of SSH in models, but also an opportunity to have global observations of the 2D structure of these phenomena, and to learn more about their interactions. At these small scales, ocean dynamics evolve rapidly, and combining SWOT 2D SSH data with other satellite or in situ data with different space-time coverage is also a challenge. SWOT’s new technology will be a forerunner for the future altimetric observing system, and so advancing on these issues today will pave the way for our future.

Thumbnail Image
Article

SEASTAR: A mission to study ocean submesoscale dynamics and small-scale atmosphere-ocean processes in coastal, shelf and polar seas

2019-08-13 , Gommenginger, Christine , Chapron, Bertrand , Hogg, Andy , Buckingham, Christian , Fox-Kemper, Baylor , Eriksson, Leif , Soulat, Francois , Ubelmann, Clement , Ocampo-Torres, Francisco , Nardelli, Bruno Buongiorno , Griffin, David , Lopez-Dekker, Paco , Knudsen, Per , Andersen, Ole , Stenseng, Lars , Stapleton, Neil , Perrie, Will , Violante-Carvalho, Nelson , Schulz-Stellenfleth, Johannes , Woolf, David K. , Isern-Fontanet, Jordi , Ardhuin, Fabrice , Klein, Patrice , Mouche, Alexis , Pascual, Ananda , Capet, Xavier , Hauser, Daniele , Stoffelen, Ad , Morrow, Rosemary , Aouf, Lotfi , Breivik, Øyvind , Fu, Lee-Lueng , Johannessen, Johnny A. , Aksenov, Yevgeny , Bricheno, Lucy , Hirschi, Joel , Martin, Adrien C. H. , Martin, Adrian P. , Nurser, A. J. George , Polton, Jeff , Wolf, Judith , Johnsen, Harald , Soloviev, Alexander , Jacobs, Gregg A. , Collard, Fabrice , Groom, Steve , Kudryavtsev, Vladimir , Wilkin, John L. , Navarro, Victor , Babanin, Alexander , Martin, Matthew , Siddorn, John , Saulter, Andrew , Rippeth, Tom P. , Emery, Bill , Maximenko, Nikolai , Romeiser, Roland , Graber, Hans C. , Alvera Azcarate, Aida , Hughes, Chris W. , Vandemark, Douglas , da Silva, Jose , Van Leeuwen, Peter Jan , Naveira Garabato, Alberto C. , Gemmrich, Johannes , Mahadevan, Amala , Marquez, Jose , Munro, Yvonne , Doody, Sam , Burbidge, Geoff

High-resolution satellite images of ocean color and sea surface temperature reveal an abundance of ocean fronts, vortices and filaments at scales below 10 km but measurements of ocean surface dynamics at these scales are rare. There is increasing recognition of the role played by small scale ocean processes in ocean-atmosphere coupling, upper-ocean mixing and ocean vertical transports, with advanced numerical models and in situ observations highlighting fundamental changes in dynamics when scales reach 1 km. Numerous scientific publications highlight the global impact of small oceanic scales on marine ecosystems, operational forecasts and long-term climate projections through strong ageostrophic circulations, large vertical ocean velocities and mixed layer re-stratification. Small-scale processes particularly dominate in coastal, shelf and polar seas where they mediate important exchanges between land, ocean, atmosphere and the cryosphere, e.g., freshwater, pollutants. As numerical models continue to evolve toward finer spatial resolution and increasingly complex coupled atmosphere-wave-ice-ocean systems, modern observing capability lags behind, unable to deliver the high-resolution synoptic measurements of total currents, wind vectors and waves needed to advance understanding, develop better parameterizations and improve model validations, forecasts and projections. SEASTAR is a satellite mission concept that proposes to directly address this critical observational gap with synoptic two-dimensional imaging of total ocean surface current vectors and wind vectors at 1 km resolution and coincident directional wave spectra. Based on major recent advances in squinted along-track Synthetic Aperture Radar interferometry, SEASTAR is an innovative, mature concept with unique demonstrated capabilities, seeking to proceed toward spaceborne implementation within Europe and beyond.

Thumbnail Image
Article

Integrated observations of global surface winds, currents, and waves: Requirements and challenges for the next decade

2019-07-24 , Villas Bôas, Ana B. , Ardhuin, Fabrice , Ayet, Alex , Bourassa, Mark A. , Brandt, Peter , Chapron, Bertrand , Cornuelle, Bruce D. , Farrar, J. Thomas , Fewings, Melanie R. , Fox-Kemper, Baylor , Gille, Sarah T. , Gommenginger, Christine , Heimbach, Patrick , Hell, Momme C. , Li, Qing , Mazloff, Matthew R. , Merrifield, Sophia T. , Mouche, Alexis , Rio, Marie H. , Rodriguez, Ernesto , Shutler, Jamie D. , Subramanian, Aneesh C. , Terrill, Eric , Tsamados, Michel , Ubelmann, Clement , van Sebille, Erik

Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it outlines observational gaps that limit our current understanding of coupled processes that happen at the air-sea-ice interface. A significant challenge for the coming decade of wind, current, and wave observations will come in combining and interpreting measurements from (a) wave-buoys and high-frequency radars in coastal regions, (b) surface drifters and wave-enabled drifters in the open-ocean, marginal ice zones, and wave-current interaction “hot-spots,” and (c) simultaneous measurements of absolute surface currents, ocean surface wind vector, and directional wave spectrum from Doppler satellite sensors.